1. Field of the Invention
The present invention relates to an acoustic apparatus, and more particularly to an acoustic apparatus employing the principle of an acoustic lens constituted by a reflector.
2. Description of the Related Art
There has long been a demand for directing sounds so as to be heard by only a specific person or persons or at only a specific space or spaces without disturbing the surrounding people and so on. A loudspeaker as a means of amplifying sounds is generally known. Furthermore, an earphone which is inserted in the external auditory meatus is extensively employed for general use or as a hearing aid.
The principle of an acoustic lens is conventionally known: Sound waves from a sound source are applied to a variously curved reflector having a focus, and the reflected sound waves are caused to diverge or scatter. Although this principle is applicable to buildings such as outdoor and indoor concert halls, it has not been put to practical use, and its effect has not been ascertained.
However, the aforementioned earphone gives discomfort to a wearer when it is inserted into the external auditory meatus. Hence, there has been the problem that there are very many cases where persons having slight or moderate difficulty in hearing do not use the hearing aid, especially not for long hours, owing to the discomfort and are inconvenienced as a result.
In addition, as for the conventional loudspeakers, since the range of sounds issuing therefrom cannot be restricted to a specific space, the loudspeakers exert a large influence on surrounding people and so on.